MONTPELIER — Rep. Cynthia Browning, D-Arlington, is suing to gain access to the Shumlin administration’s records on efforts to construct a financing plan for a proposed universal health care system.

The administration is working to create Green Mountain Care, a universal, publicly financed health care system it hopes to launch in 2017. The administration was required by Act 48, passed in 2011, to give the Legislature a financing plan by Jan. 15, 2013, but it has not.

Browning, a fellow Democrat who opposes Gov. Peter Shumlin’s plan, has been the most outspoken lawmaker in pushing him to reveal how the health care system will be paid for — or at least share the work his health care team has completed so far.

Shumlin has repeatedly said, however, that a plan has not been finished and will not be released until it has been finalized.

Browning filed a public-records request last month with the administration seeking the information. That request was denied by the deputy director of health care reform, Michael Costa. Her appeal of Costa’s denial was rejected by Secretary of Administration Jeb Spaulding.

The administration cited executive privilege as the basis for rejecting Browning’s request because the information sought reflects “communications in the course of the governor’s decision-making process that may be withheld to protect the governor’s consultative and decisional responsibilities.”

Browning said her lawsuit, filed Wednesday by Montpelier attorney Paul Gillies, a former Vermont deputy secretary of state, argues the documents and information sought regarding the financing plan are already public.

“By establishing a date on which such records would become public, the legislature has converted what would otherwise be privileged records into public records,” the lawsuit asserts.

Shumlin, speaking at his weekly news conference Wednesday, said he was not aware of Browning’s filing.

“I’m not going to comment on something that I’ve only heard about from all of you,” the governor said.

Shumlin said his administration will present its plan early next year.

“We will welcome the opportunity to be ready with a financing plan when the next biennium considers the question,” he said. “It’s not that I’m fighting the release, it’s that we don’t have anything to release. We don’t have a plan ready for prime time.”

The House on Wednesday debated an omnibus health care bill that would set a new date in February 2015 for the governor to release his plan. Rep. Michael Fisher, D-Lincoln, chairman of the House Health Care Committee, acknowledged on the House floor when reporting the bill that Shumlin failed to meet Act 48’s requirement to provide a financing plan.

“It’s clear that the report provided to the Legislature did not meet that goal,” Fisher said. “And it is also clear to me that, from my perspective, that January (2013) was not the right date to ask for that report.”

The legislation would force Shumlin to present his financing plan in February, and if he does not, lawmakers will slam on the brakes, Fisher said.

“We have set a date with some enforcement behind it,” he said. “If it does not come to us at that time it’s clear that we’re not moving forward with Green Mountain Care.”

Browning tried to amend the bill to require Shumlin to present the plan by May 9 — just over a week away.

The amendment, which was rejected, also sought subpoena power for the House Ways and Means and Senate Finance committees to compel the administration to produce its work if it failed to do so voluntarily.